COMPASS/BEIDOU 2B
E2 Code Generators
Grace Gao, Alan Chen, Sherman Lo, and Per Enge
On April 13, the first Medium
Earth Orbit (MEO) satellite of the Compass GNSS system was launched on April 13, 2007.
The satellite orbits at an altitude of 21,550 kilometers above the
Earth. Conventionally designated Beidou 2B, it has been observed to transmits
on 3 distinct frequencies: 1561.1MHz, 1268.52 MHz, 1207.14MHz.
The 1561.1 MHz signal (essentially the Galileo E2 band) is a BPSK(2)
signal. At Stanford University, we collected signals from the
satellite on May 7, 2007 using the Stanford
GNSS Monitor Station (SGMS). The results were processed in a similar
manner to the GIOVE-A code to determine the COMPASS code.
Figure 1. Spectrum of COMPASS E2 centered at 1561.1 MHz from data
collected using the SGMS
•
E2 code:
2046 chips, 1ms, Gold code
Polynomial 1: X11+X10+X9+X8+X7+X+1
Polynomial 2: X11+X9+X8+X5+X4+X3+X2+X+1
Initial state 1: [0 1 0 1 0 1 0 1 0 1 0 ]
Initial state 2: [0 0 0 0 0 0 0 1 1 1 1]
LINKS
COMPASS E6 Code, (TO BE CREATED LATER)
References
[1]. Thomas Grelier, Joel Dantepal, Antoine Delatour, Alain Ghion, and Lionel
Ries, "Initial Observations and Analysis of the Compass MEO Satellite Signals",
InsideGNSS June 2007
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